Fast Bullet Script for Unity3d

Bullet

using UnityEngine;
using System.Collections;

public class Bullet : MonoBehaviour
{
    public enum BulletType
    {
        energy,
        fire,
        freeze,
        laser,
        missile,
        flash,
    }

    private Vector3 _target;
    private float Speed=2f;
    private float distance = 0f;
    private Vector3 startPosition;
    public BulletType Type;
    private float range=0f;
    private int level;
    private int Damage;
    private int number;

    private Transform T;
    private Vector3 tempPosition=new Vector3();

    public int reflection_count = 0;
	// Use this for initialization
    void Awake()
    {
        T = transform;
        if (Random.value > 0.5f)
        {
            number = 1;
        }
        else
        {
            number = 0;
        }
    }
	void Start () {
	
        //_target=new Vector3(transform.position.x,transform.position.y,transform.position.z);

	   // iTween.MoveTo(gameObject,_target,1f);

        Invoke("DestroyBullet",5f);
	    startPosition = T.position;

        if (Type == BulletType.missile)
        {
            Speed = 1.5f;
        }
	    //SoundController.Instance.LaserSound();

	}
	
	// Update is called once per frame
	void FixedUpdate () {

        //Fix performance

      
        tempPosition.x =Mathf.Lerp(startPosition.x, _target.x,distance);
        tempPosition.y = Mathf.Lerp(startPosition.y, _target.y, distance);

        float mody=0f;
        float modx = 0f;

        if (Type == BulletType.energy)
        {
            if (Mathf.Abs(_target.x) > Mathf.Abs(_target.y))
            {
                if (number == 0)
                {
                    mody = Mathf.Sin(tempPosition.x*0.5f) * 3;
                }
                else
                {
                    mody = Mathf.Cos(tempPosition.x*0.5f) * 3;
                }
                tempPosition.y += mody;
            }
            else
            {
                if (number == 0)
                {
                    modx = Mathf.Sin(tempPosition.y*0.5f) * 5;
                }
                else
                {
                    modx = Mathf.Cos(tempPosition.y*0.5f) * 5;
                }

                tempPosition.x += modx;
            }
            
        }

        if (Type == BulletType.flash)
        {
            if (number == 0)
            {
                mody = Mathf.Sin(tempPosition.x * 0.5f) * 20*distance;
            }
            else
            {
                mody = Mathf.Cos(tempPosition.x * 0.5f) * 20*distance;
            }
            tempPosition.y += mody;
        }

       
      
        distance += Speed*0.01f;

        T.position = tempPosition;
    }

    public void SetNumber(int c)
    {
        number = c;
    }
	public void setTarget(Vector3 v)
	{
		_target=v;

		//Debug.Log("target is:"+_target);
	}

    public void setDamage(int damage)
    {
        Damage = damage;
    }

    public int getDamage()
    {
        return Damage;
    }

    public void SetLevel(int l)
    {
        level = l;
    }
    public int GetLevel()
    {
        return level;
    }
    public void setRange(float r)
    {
        range = r;

    }
    void DestroyBullet()
    {
            gameObject.SetActive(false);
    }
}